From the turn of the century until the late 1960's, the only ways available to examine and take biopsy samples from a patient's lungs was either by surgery or through a rigid metal bronchoscope. In 1967, Ikeda, in Japan, introduced the first flexible fiberoptic bronchoscope (FFB). Over the last 20 years, as technological limitations and additional physician needs became evident, the FFB has undergone extensive revision and development.
Flexible Fiberoptic Bronchoscopy (FIG. 1, 10) is One of the most versatile tools available today in the evaluation of lung disease. Developed in the late l960's, the Flexible Fiberoptic Bronchoscope (hereinafter equivalently referred to as FFB) enables Pulmonary Physicians to examine, under direct visualization, the oropharynx, vocal cords, trachea and main bronchial divisions of the bronchial tree. Through the Bronchoscope various biopsy tools, including brushes, forceps 27, and curettes may be passed to obtain samples of tissue from the visible airways and the pulmonary parenchyma. Diagnoses of cancer, tuberculosis and other infections, foreign body aspiration, airway obstruction and many other pulmonary disorders can be achieved relatively quickly, thoroughly and painlessly. Unlike rigid bronchoscopy or open lung biopsy, which must be done under general anesthesia, FFB is performed on an awake patient using local anesthesia, with proportionally less morbidity and mortality.
The procedure itself is relatively simple, and is usually done with the patient sedated, but awake. The Bronchoscope is passed either through the nose with the patient sitting, or through the mouth with the patient supine. As the scope is passed through the upper airway and the vocal cords, all visible sites are carefully examined, and biopsies are taken of any suspicious lesions. Upon entering the trachea, the methodical search is continued, of the trachea itself, the carina (the junction between the left and right lungs), the left and right main bronchii and all of the subsegments of both lungs. Next, under fluoroscopic guidance, lesions beyond the reach of the bronchoscope are located, biopsy tools are passed out into these lesions and samples are taken. Depending on the indication, it is also possible to wash out various parts of the lung and to send the fluid reclaimed for special diagnostic lab tests. After the examination is completed and all relevant specimens are obtained, the FFB is removed and the patient is observed, usually in hospital, for 12 to 24 hours for the development of complications. These are uncommon, and include persistent bleeding, pneumothorax (collapse of the lung on the side biopsied if the outer lining of the lung is unintentionally torn), or worsening of respiratory failure.
The entire procedure takes approximately 45 minutes, is painless and relatively easy in the hands of a skilled Bronchoscopist. It has rapidly become vital as a diagnostic and therapeutic tool, and has almost completely replaced other more invasive procedures in obtaining tissue samples in the majority of lung diseases.
A typical FFB 10 measures 790 mm in length and has two main parts; a working head 14 and an insertion tube 11. The working head contains the eyepiece 15, the ocular lens with a diopter adjusting ring 25, the attachments for the suction tubing 24 and suction valve 21 and for the cold halogen light source 16 and 18, and the access port, or "biopsy inlet" 19, through which various forceps, brushes and fluids can be passed into the suction/forceps channel 29 and out the distal end of the bronchoscope. This working head is attached to the second part, the insertion tube. This tube, on the average, measures 580 mm in length and has a diameter of 6.3 mm, and contains the fiberoptic bundles (which terminates in the objective lens 30 at the distal tip 12) , the two light guides 31 and the suction/forceps channel 29. The distal end of the FFB has the ability to bend anterior and posterior only, the exact angle of deflection depending on the instrument used. A common range is from 160 degrees forward to 90 degrees backward, for a total of 250 degrees. The small bending radius is illustrated in FIGS. 3A and 3B as 13. The bending is controlled by the operator by adjusting the angle lock lever 22 and angulation lever 23 on the working head. However, unlike fiberoptic gastroscopes and colonoscopes, the bronchoscopic has no lateral deflection and, to direct it towards the right or the left, which is often necessary during certain procedures, (i.e. obtaining a biopsy sample), the entire instrument must be rotated by the operator.
Through the suction/forceps channel, many devices, such as biopsy forceps and brushes, can be passed through the length of the bronchoscope, exiting from its tip into a patients lungs, and are used to obtain samples. Brushes of different sizes, shapes and material (typically wire) can be passed into the airways of the lung, segments brushed and the sediment on the brush tip sent off to the laboratory for examination.
The typical biopsy forceps consists of a handle at one end connected to a long, flexible shaft 28 with an enhanced distal flexible segment and, at its distal end, two sharpened "cups" 27 (the forcep) which appose upon one another. When the ring at the handle end is pulled back, an inner wire or cable contained within the outer cable of the shaft slides backwards, opening the cups. Manipulating the FFB, the open forceps are then positioned (often with great difficulty since the bronchoscope has no lateral deflection), as close as possible to where one wants to obtain a sample, the ring is slid forward and the cups close. The forceps are then forcibly withdrawn, hopefully tearing off a small piece of the desired sample (i.e. tissue) of lung.
In a representative procedure, the patient is usually awake, although premedicated for sedation and drying of secretions, and is either sitting or supine. After local anesthesia is obtained by spraying Lidocaine on the nasal and oropharynx mucosa, the FFB is gradually passed through either the nose or the mouth into the posterior oropharynx, and positioned above the vocal cords. Additional Lidocaine is applied to the cords and throughout the rest of the procedure as the instrument is advanced. After careful examination of the cords and their movement, the FFB is advanced through them and is positioned in the trachea, which is also carefully anesthetized and examined. Any suspicious lesions or areas are biopsied and/or brushed. Then, in a planned, meticulous fashion, the remainder of the airways of the lungs are evaluated--from the carina, into all of the segments and accessible subsegments bilaterally and, if suspicious lesions, segments or anatomy are encountered, additional brushings and biopsies are taken. Next, under fluoroscopic guidance, brushes and forceps are advanced out beyond the range of direct vision of the FFB, into the peripheral lung, and additional samples of the lung parenchyma are removed. The biopsy sites are observed for bleeding, and, if necessary, adrenaline and saline washes are used to stop any major bleeding. If it is indicated, the FFB can also be wedged into one of the many subsegments of the lung and larger amounts of saline washed in and out, then evaluated in the laboratory for infection, malignancy, or other desired tests. After meticulous hemostasis is achieved, the FFB is withdrawn and the procedure is ended. Depending on the numbers of biopsies taken and the difficulty of the procedure, an average bronchoscopy takes from 30 minutes to an hour.
Over the last 20 years both the bronchoscope itself and ancillary tools like the biopsy forceps have undergone major, constant revision. There are many forceps commercially available today; ones with holes cut out of the cups; ones with jagged "alligator" jaws, designed for tearing off larger pieces of tissue; ones with needles jutting from between the cups, that are used to jab growths that are difficult to reach; and grasping forceps with interlocking teeth. There also exist double-jointed curettes which articulate only in an uncontrolled manner upon pressure to the extreme distal tip. The pressure is applied by forcing the entire biopsy forcep distal end against an internal obstruction. The distal end is realigned only by either forcing it against another obstruction, the walls of the trachea or by pulling it back into the biopsy channel. The double hinge is not otherwise controllable by the operator. This curette is clumsy and rarely used by practitioners.
Although all of these variations on the basic design of the forceps have their uses, there remains one very clear cut, specific dilemma that is encountered practically daily that no modification to date has yet been able to resolve.
The average internal diameter of the trachea in an adult man measures 12 mm, the right main bronchus 12-16 mm and the left main bronchus 11-14 mm. As noted above, the diameter of a representative bronchoscope measures 6.3 mm, occupying over half of the airway and leaving a very tight space to work within. The approach to lesions that arise directly ahead of the tip of the FFB is straightforward, and easily accessible without much manipulation of the bronchoscope.
However, it is very difficult, and often impossible, to take biopsies of smooth growths that arise off the walls of the trachea or of the main stem bronchii. The exit channel for the biopsy forcep is at the tip of the FFB, and the forceps itself can only be aimed by directing the FFB itself. As mentioned above, the tip of the FFB is only able to deflect in the anterior and posterior directions. Within the confines of the airways, the tip of the FFB is often only able to be flexed 30 to 40 degrees. In addition, looking down through the bronchoscope, the exit channel is placed at a "9:00" (on a clock, directly to the left, or west on a map) position and any tools passing through it come out from there. In order to sample lesions that arise off the right wall, the FFB must be rotated 180 degrees upon itself, and the operator is then essentially working upside down. This is a very difficult, clumsy position to maneuver in, may be additionally uncomfortable to the patient and often gives inadequate results.
Smooth lesions, and most mucosal growths are smooth, typically arise off the wall at an oblique angle, and the metal cups of the forceps slide off them, frustrating repeated attempts at taking biopsy specimens. In addition, mucosal growths are not fixed into position, therefore attempts made to stab them with the needle forceps only push them away. Unless the tip of the FFB can be flexed enough so that the lesion can be approached directly head on, (roughly approaching 90 degrees, which is essentially out of the designed range of the FFB) within these small work spaces, repeated attempts at sampling often end in failure.
It is also important to note that the biopsy channel of the FFB is a long, narrow channel. It is impossible to pass through it any device with a fixed angle built into its tip. Therefore, it has proven necessary to provide a device such as a Biopsy Forceps that is flexible enough to allow passage through the FFB.
Sometimes it is impossible to maneuver the FFB into the necessary position to obtain samples. If a tissue diagnosis cannot be made using Bronchoscopy, the patient must then undergo surgery to reach a definitive diagnosis.
It is therefore an object of the present invention to provide a biopsy forceps for use through a flexible fiberoptic bronchoscope, which would enable one to biopsy smooth growths that arise off the wall of the trachea or of the main stem bronchii easily and directly.
It is a further object of this invention that the biopsy forceps for removal of these smooth growths would be utilizable in a standard flexible fiberoptic bronchoscope and would enable the operator to obtain such biopsy samples without the need to orient himself in a cumbersome position.